The present invention relates to an iron-based sintered alloy which is wear-resistant at high temperature. Such sintered alloy is preferably used as a material for mechanical parts (e.g., such as valve seat insert used in internal combustion engine) that require wear resistance at high temperature.
There are various conventional wear resistant materials. For example, Japanese Patent Examined Publication JP-B-5-55593 and Japanese Patent Unexamined Publication JP-A-7-233454 disclose high-temperature wear-resistant sintered alloys each being high in cobalt content. However, the production cost of these sintered alloys is high, due to the use of relatively large amounts of cobalt.
JP-A-5-9667 discloses an iron-based sintered alloy containing an iron-based matrix and an iron-based hard phase dispersed in the matrix. The hard phase contains C, Cr, Mo, W, V, Si, and Mn. JP-B-1-51539 discloses an iron-based sintered alloy containing an iron-based matrix and a dispersed phase containing Cr, C, Mo, Si, and at least one selected from Nb, Ta, Ti and V. According to these patent publications '667 and '539, however, it is difficult to prepare a sintered alloy that is superior in wear resistance and at the same time is weak in the property of damaging another member that is in contact with the sintered alloy.